The following is a tabulation of some prior art that presently appears relevant:
U.S. patentsPat. No.Kind CodeIssue DatePatentee885,288Apr. 21, 1908Robert G. Ping935,206Sep. 28, 1908Amos K. Holdeman3,257,756Jun. 28, 1966Marvin R. Mealer4,791,757Dec. 20, 1988Paul F. OrlandoDes. 251,702May 1, 1979Leo J. MartiniU.S. Pat. No. B1Sep. 1, 2009Bruce G. Gill, 7,581,353Douglas J. Blanchard3,613,314Oct. 19, 1971Francis L. Ford